Spunbonded nonwoven fabric

ABSTRACT

A spunbonded nonwoven fabric having a silicone-glycol copolymer thereon is disclosed. Of particular interest is the spunbonded nonwoven polypropylene fabric used as carpet backing.

United States Patent 1191 Campbell et a1.

SPUNBONDED NONWOVEN FABRIC Inventors: ,Paul E. Campbell, Greensboro,

' N.C.; John G. Kokoszka, Midland,

Mich.

Assignee: Dow Corning Corporation, Midland,

Mich.

Filed: July 25, 1973 Appl. No: 382,601

us. 01.. ..117 /l38.8 F, l17/138.8 E, 117/1388 N, 117/1395 cQ. 117/161 ZA Int. Cl B44d 5/08, C08g 31/18 Field of Search... 117/138.8 E, 138.8 F, 139.5

3,140,198 7/1964 Dawson'et a1. 117/1388 1 Feb. 18, 1975 Jung 161/67 Pikula 117/138.8 Petersen 161/150 Edwards 161/57 Buster etal 252/89 Sands 260/29.1 SB

Daniel 117/1388 E Primary Examiner-4. E. Willis, Jr. Attorney, Agent, or Firm-Jack E. Moermond ABSTRACT interest is the spunbonded nonwoven polypropylene,

fabric nsed as carpet backing.

13 Claims, No Drawings SPUNBONDED NONWOVEN FABRIC A spunbonded fabric is a continuous filament nonwoven fabric made by combining all the steps from polymer to finished fabric in one process. Curtains of filaments are extruded, drawn, forwarded to a belt and combined there into a web with the required design. The web is then bonded and can be finished in the same single process.

The basic process steps for making spunbonded nonwoven fabrics are quite simple. Multiple spinnerettes extrude large numbers of filaments which are drawn and oriented'by rolls or high velocity air, in groups and then projected in some desired geometrical array onto a slower moving porous belt provided with suction to hold down the filaments. The belt then carries the web to a bonding operation (heater rolls, binder application, etc.) and then to a series of further operational steps in the process. These latter can be the traditional .textile finishing steps such'as printing or embossing when process speeds are compatible. From there the fabric is inspected, wound up and packaged.

There are many spunbonded nonwoven fabrics avail able commercially. Examples of such materials are those based on polyesters, polypropylene, polyethylene, nylon or combinations of the foregoing. The particular fiber type used will depend on the nature of the finished product one wishes to make. End uses for spunbonded nonwoven fabrics ranges from such things as book covers, to clothing fabric to carpet backing.

This invention relates to a spunbonded nonwoven fabric having thereon a silicone-glycol copolymer having the general formula (Cl-l SiO{(CH SiO},- {(CH )GSiO} ,,Si(CH wherein G is a radical of the structure -R(OC H Ol-l, R is an alkylene radical containing from 1 to 18 carbon atoms, .t has an average value of from 40-90, y has an average value of from l-lO. and has an average value of from l-l0.

This invention also relates to a spunbonded nonwoven polyolefin fabric having thereon a silicone-glycol copolymer having the general formula set forth above.

This invention still further relates to a spunbonded nonwoven polypropylene carpet backing having thereon a silicone-glycol copolymer having the general formula set forth above.

Other aspects of this invention and the objects thereof will be apparent to those skilled in the art from the following more detailed disclosure and description of the invention.

One of the most significant commercial uses of spunbonded nonwoven fabric has been the use of spunbonded nonwoven polypropylene as a carpet backing. The spunbonded nonwoven polypropylene fabric has been substituted for the woven jute backing materials that have been used heretofore in the production of carpets. ln this process the carpet yarn is threaded through a large needle which punches through the spunbonded nonwoven polypropylene fabric which is designated as the primary backing. A looper device catches the yarn on the under side to form loops or tufts and the needle is then withdrawn. The backing fabric is then advanced and the cycle is repeated to form additional tufts. The tufts make up the pile or face of the final carpet. A commercial tufting machine may have up to 2,400 needles in a row all working in unison to make a carpet up to feet in width. The primary backing, which is the spunbonded nonwoven polypropylene, is the structural base of the carpet. It hold the tufts in place and provides dimensional stability and strength to the carpet. To the back of the tufted spunbonded nonwoven polypropylene there is added a glue or latex coating, for example, natural rubber or styrene hutadiene rubber, which coating'firmly anchors the tufts in place and keeps them from pulling out. A final jute or foam back may then be placed on the carpet to act as a pad or cushion. In the development of this use of the spunbonded nonwoven fabric it was found that the needles did extensive damage to the carpet backing on penetration of the structure resulting in a large loss in strength during the tufting process. It was then discovered that by the application of a methyl hydrogen polysiloxane fluid to the spunbonded nonwoven polypropylene carpet backing that the penetration of the needle through the carpet backing in the tufting process was facilitated and that the fiber damage and loss of strength which resulted therefrom could be significantly reduced.

A number of difficulties were encountered, however, with the use of the methyl hydrogen polysiloxane fluid. The most severe of these difficulties was encountered during the dyeing process for carpets employing the spunbonded nonwoven polypropylene carpet backing. More specifically, in the Kiis'ters continuous dyeing process (foam dyeing with steam) for carpets the methyl hydrogen polysiloxane fluid on the carpet backing reduced the foam level in the system resulting in nonuniform dyeing of the carpet. Other problems were the reduced wettability of the carpet, a tendency for the carpet to float in aqueous systems, the relative flammability of the carpet, and the high cost of the methyl hydrogen polysiloxane fluid employed.

It has been found in accordance with this invention that when the silicone-glycol copolymer having the general formula set forth above is employed in place of the methyl hydrogen polysiloxane fluid employed heretofore that not only is good lubricity obtained facilitating needle penetration through the carpet backing during the tufting process but also the problems involved in the dyeing of the carpet in the Kuster system are significantly reduced if not entirely eliminated.

As can be seen from the general formula set forth above the silicone-glycol copolymer which produces the results and advantages of this invention is a trimethylsilyl endblocked siloxane which can contain from 409O dimethylsiloxane units therein and from 1-10 methylglycol units. The copolymers useful herein are water insoluble. The water soluble silicone-glycol copolymers wet the latex backing too much allowing it to penetrate the polypropylene backing too far resulting in a poor carpet.

The glycol units are represented in the general formula by the symbol G which is more specifically defined as having the structure -R((OC H.,-) OH. The R radical in this structure can be any alkylene unit containing from 1-18 carbon atoms. Thus, for example, R can be a methylene, ethylene, propylene, butylene, isobutylene, hexylene, decylene, dodecylene or an octadecylene radical. The glycol portion represented by the (OC H portion ofthe structure is as can be seen from the formula a propylene glycol. This glycol is hydroxyl endblocked or as is commonly stated in the art an uncapped glycol. As indicated there can be an average of from l10 propylene oxide units making up the glycol portion of the structure, i.e., 2 has an average value of from 1-10. It is preferred, however, that z have an average value of from l5.

Themethyl-glycol units in the silicone-glycol copolymer can range from an average value of 1-10 which is to say y can have a value from l lO. However, it is generally preferred that the average value of y be in the range of from 1-5. The subscript can have an average value of from 40-90 but preferably ranges in value from 5075. The subscript .t defines the number of dimethylsiloxane units in the silicone-glycol copolymer.

Based on the disclosure of the structure herein the preparation of the silicone-glycol copolymer set forth above will be obvious to those skilled in the art of the preparation of such materials.

The silicone-glycol copolymer can be applied to the spunbonded nonwoven fabrics by any of the well known techniques for applying finishes to fabrics and textile materials. However, the use of a gravure roll is the preferred method at this time. The amount applied to the fabric will depend to some extent on the desired results but generally speaking will fall within the range of 0.1- percent by weight based on the weight'of-the fabric. However, it is believed that generally an amount in the range of 0.55 percent will meet most needs. The

silicone glycol copolymer can be applied to the fabric neat or in the forma solution in a suitable carrier such as water (emulsified), the lower alcohols, ethers, ketones and other water compatible solvents.

Now in order that those skilled in the art may better understand how the present invention can be practiced the following examples are given by way of illustration and not by way oflimitation. All parts and percents referred to herein are by weight and all viscosities measured at C. unless otherwise specified.

EXAMPLE I A silicone-glycol copolymer having the general formula (CH2 a 5 s) was applied to a spunbonded nonwoven polypropylene carpet backing using a gravure roll. A pickup of about 1% of the silicone-glycol copolymer, based on the weight of the carpet backing, was achieved. A piece of tufted carpet was then made from this treated backing It was found that the needle lubricity provided by this silicone-glycol copolymer during the tufting process EXAMPLE 2 The silicone-glycol copolymer of Example I was applied via gravure roll to a spunbonded nonwoven polypropylene carpet backing with a 4% pickup or add-on being obtainedjA piece of tufted carpet was then made from this treated backing and allowed to age for seven weeks before dyeing it by the Kuster process. In the dyeing process the foam started, in 5 seconds, reached a height of 2 inches, had a life of seconds, and was of very good quality. In short, no problem was encountered in the dyeing of this carpet.

By comparison the spunbonded nonwoven polypropylene carpet backing having a 3% add-on ofa methyl hydrogen polysiloxane fluid by gravure roll and made into atufted carpet, could not be dyed by the Kiister process'because no foam formed due to the presence of this siloxane. This test was conducted after the treated carpet had aged one week.

Note that more of the silicone-glycol copol mer of this invention was added on and hence its antifoaming action would have been expected to be more severe. And secondly, the sample of this invention was aged longer as the spunbonded nonwoven polypropylene carpet backing tends to become more difficult to dye with age after finishing.

EXAMPLE 3 When the following silicone-glycol copolymers are substituted for the one used in the preceding examples. a spunbonded nonwoven polypropylene carpet backing is obtained which provides excellent needle lubricity during tufting, and which can be dyed by the Kuster process without causing significant defoaming.

l (CH2)3 a s)1 Continued EXAMPLE 4 When 2% of a silicone-glycol copolymer having the general formula 5. A fabric as defined in claim 4 which is a polyolefin fabric.

6. A fabric as defined in claim 5 which is selected CH2CH(CH3 )CHz Ca s)5 wherein G is a radical of the structure -R(OC H,,) OH, R is an alkylene radical containing from 1 to [8 carbon atoms,

x has an average value of from 40 to 90.

y has an average value of from I to l(), and

Z has an average value of from I'm [0.

2. A fabric as defined in claim 1 wherein R'contains from 3 to 6 carbon atoms, xhas an average value from 50 to 75, y has an average value from 1 to 5, and z has an average value from 1 to 5.

3. A fabric as defined in claim 2 wherein R contains 3 carbon atoms, .r has an average value of about 67, y has an average value of about 3, and 1 has an average value of about 2.5.

4. A fabric as defined in claim 1 which is selected from the group consisting of polyester fabrics and polyolefin fabrics.

from the group consisting of polyethylene and polypro pylene fabrics.

7. A fabric as defined in claim 6 which'is a ene fabric.

8. A fabric as defined in claim 6 which isa polypropylene fabric. 7 1

polyethyl- 9. A fabric as defined in claim 8 wherein R contains from 3 to 6 carbon atoms, x has an average value from 50 to 75, v has an average value from l to 5, and 1 has an average value from I to 5.

10. A fabric as defined in claim 9 wherein R contains 3 carbon atoms, has an average value of about 67. y has an-average value of about 3, and ,1 has an average value of about 2.5.

11. A fabric as defined in claim 8 which is a carpet 

1. A SPUNBONDED NONWOVEN FABRIC HAVING THEREON A SILICONE-GLYCOL COPOLYMER HAVING THE GENERAL FORMULA
 2. A fabric as defined in claim 1 wherein R contains from 3 to 6 carbon atoms, x has an average value from 50 to 75, y has an average value from 1 to 5, and z has an average value from 1 to
 5. 3. A fabric as defined in claim 2 wherein R contains 3 carbon atoms, x has an average value of about 67, y has an average value of about 3, and z has an average value of about 2.5.
 4. A fabric as defined in claim 1 which is selected from the group consisting of polyester fabrics and polyolefin fabrics.
 5. A fabric as defined in claim 4 which is a polyolefin fabric.
 6. A fabric as defined in claim 5 which is selected from the group consisting of polyethylene and polypropylene fabrics.
 7. A fabric as defined in claim 6 which is a polyethylene fabric.
 8. A fabric as defined in claim 6 which is a polypropylene fabric.
 9. A fabric as defined in claim 8 wherein R contains from 3 to 6 carbon atoms, x has an average value from 50 to 75, y has an average value from 1 to 5, and z has an average value from 1 to
 5. 10. A fabric as defined in claim 9 wherein R contains 3 carbon atoms, x has an average value of about 67, y has an average value of about 3, and z has an average value of about 2.5.
 11. A fabric as defined in claim 8 which is a carpet backing.
 12. A fabric as defined in claim 11 wherein R contains from 3 to 6 carbon atoms, x has an average value from 50 to 75, y has an average value from 1 to 5, and z has an average value from 1 to
 5. 13. A fabric as defined in claim 12 wherein R contains 3 carbon atoms, x has an average value of about 67, y has an average value of about 3, and z has an average value of about 2.5. 